This proposal aims to study regulation of biosynthesis of human chorionic gonadotropin (hCG), its processing and secretion. Among parameters that might influence the regulation of the levels of this hormone throughout placental development are those involved in both the transcriptional and the translational levels. Thus we plan to measure ribosome transit time for average protein and specific ribosome transit time for alpha- and beta-hCG throughout placental development as translational parameters that might influence gene expression. The possible role of tRNA in regulating hCG synthesis during placental development will be studied. The possibility that changes in membrane during development might influence the rate of processing of hCG will be studied. The rate of translation will be correlated to the rate of transcription by quantitating polysomal alpha- and beta-hCG messenger RNA during placental development.